The signatures that make up a book are fed to the binding line by feeder devices of a particular type or types. Typically, these feeder devices comprise what are referred to as packer boxes, but the line may also include one or more card feeders for inserts, and will usually include at least one cover feeder to feed covers for the book. As will be appreciated, the composition of the book can be varied by the selective activation of these feeder devices.
In addition to customizing the composition of the book, address labels, personalized messages and other graphics can be printed onto the pages of a book on the binding line by utilizing ink jet printers. To further customize the book, the selection of print location and the print content can be specified by code in accordance with the teachings of commonly owned U.S. Pat. No. 4,121,818. At the end of the binding line, books can be bundled by mail route in order to maximize postal discounts since the production order at the binding line will typically have been presorted by zip code for this purpose.
Of course, it will be appreciated that defective books that must be reordered, i.e., remade, should also be properly bundled at the end of the binding line. This can be handled in accordance with the teachings of commonly owned U.S. Pat. Nos. Re. 32,690 and 4,674,052 which take into account that each book on the line can have a unique combination of characteristics including composition, ink jetted image and mail bundle. Because of this fact, the action of a binding line device is dictated at any machine cycle by the unique characteristics of the book currently at that device.
Currently known saddle-wire binding lines can accurately be characterized as fully synchronized assembly lines. A slotted conveyor chain carries a book past stationary binding line devices which operate on the chainspaces that are directly under their respective positions at any point in time, e.g., they may drop a signature onto the chainspace or print a message onto the book riding on the chainspace. As a result, the operations of all stationary binding line devices are synchronized to the motion of the chain.
As a practical matter, multiple conveyor chains are typically used to transport a book through such a binding line. However, the drive shafts of all such conveyor chains are fully coupled to effectively produce a single continuous chain loop.
In a typical saddle-wire binding line, the continuous chain loop is divided into chainspaces by what are known as push pins. As the chain conveyor moves, chainspaces can be described as being "created" at the head of the binding line, driven through the binding line by the drive shaft, and "expelled" at the end of the binding line; thus, during its "life span" in the binding line, a chainspace serves to carry a single book. In this connection, a book is positively confined to a single chainspace as it passes through the binding line.
Thus, the characteristics of a continuous chain loop are such that the distance a book moves is derivable from the rotation of the drive shaft. This follows from the fact that the chain is driven by the drive shaft and, as a result, a binding line may, by way of example, be geared such that each revolution of the drive shaft advances the chain by one chainspace. Accordingly, the position of a book on a binding line can be determined by measuring the number of machine cycles, i.e., drive shaft revolutions.
In other words, the continuity of the chain allows the position of a particular chainspace at any point in time to be derived from drive shaft rotation. From this, and considering the positive confinement of a book to a particular chainspace, the position of a book can be mapped to the position of its chainspace, a technique known as indirect book tracking. However, since such a binding line is locked to one drive shaft, the entire line must be stopped to interrupt the operation of any single device.
For this reason, it would be desirable to be able to utilize multiple conveyors to transport books through a binding line where the chains of the conveyors were decoupled to permit independent operation. It will be appreciated that the decoupling of conveyor chains would offer a major advantage; namely, upstream, or first, conveyor chain sections (in the direction of flow) could be stopped without affecting the operation of downstream, or second, sections. In a perfect binding line, the ability to stop the gathering section without affecting the binder section would reduce production waste due to the cooling of binder glue that would otherwise result in so-called "cold back books."
For this purpose, the gathering and binder sections could each be modeled as an independent continuous chain wherein each of the independent continuous chains has the characteristic of positive book confinement. It would not be possible, however, for the transfer mechanism that would be required to transport books from the gathering chain to the binder chain, whether it take the form of a mechanical conveyor or any other means of transferring books from one point to another, to be modeled in a similar fashion. As a result, the previously described simple method of deriving book position from drive shaft rotation cannot be applied and a method is required that can track and identify books independent of the transfer mechanism.
In addition, it may be desirable to handle a multiple number of books in one or more devices of a binding line which render it a practical impossibility to allow for the direct association of one unique book to any particular chainspace. For instance, and by way of example only, a stacking trimmer subsystem which typically includes multi-book trimmer blades together with associated stacking and unstacking devices has been so recognized inasmuch as such a subsystem permits a multiple number of books to be trimmed concurrently within the subsystem. In this connection, a stacking trimmer subsystem has its constituent components operating in concert whereby a series of individual books is stacked, a multiple number of books in the series is concurrently trimmed, and the books are unstacked to be returned as a series of individual books in the same order as the books were originally received.
For such applications, the stacking device will be positioned upstream of the multi-book trimmer and the unstacking device will be positioned downstream of the multi-book trimmer. Again, it will be understood that "upstream" and "downstream" have reference to the direction of flow of books on the binding line. Clearly, a stacking trimmer subsystem precludes tracking books by associating the identification of each book with a chainspace on which it resides as in normal processing on the binding line.
Specifically, the stacking device will typically be used to transform a series of individual books into a multiple number of books which are stacked directly on top of each other. This means that the subsystem would allow for the entire stack to be trimmed concurrently rather than requiring individual trimming of each individual book. Reciprocally, the unstacking device will typically be used to transform the books which are stacked directly on top of each other back into a series of individual books after the trimming operation.
As will be appreciated, the currently employed method of tracking books can be used for the portion of the binding line immediately upstream of the stacking device since a direct association can be made between each chainspace and a unique book. This book tracking method can also be used for the portion of the binding line immediately downstream of the unstacking device provided that the identification of each book can be determined as the books are removed from the stack. If the stacking and unstacking devices operated perfectly and there was never any spoilage in the trimmer, then a first-in, first-out tracking sequence could be used to determine the identification of the books as they are removed from the stack.
However, mishaps do occur in the stacking and unstacking mechanisms and spoilage or damage does occur occasionally in the trimming process. This may cause the series of books to become rearranged out of the first-in, first-out tracking sequence or for one or more of the books to become lost entirely. Therefore, a first-in, first-out tracking sequence may not be economically feasible for identification of books as they traverse the subsystem.
The present invention is directed to overcoming the foregoing problems and accomplishing the resulting objects by providing a unique binding line book tracking system.